Redirect log output for games using Unreal#

Multiplay Hosting expects your game to output logs to a log directory directly using the $$log_dir$$ configuration variable.

However, games using the Unreal Engine and the -Userdir launch parameter output logs to a log directory nested within $$log_dir$$/logs/Saved/Logs/ with Unreal creating the recursive directories.

Multiplay Hosting doesn't yet support traversing more than one nested log directory. To work around this, use the -LOG launch parameter to redirect to a specific file:

-LOG=../../../../$$log_dir$$/$$serverid$$.log

This causes the Unreal Engine to write to the correct directory and name the log after the specific server ID.